‘Cotton, sugar, palm oil… you name it. Most governments in the developing world believe such plantation cash crops must be a better use of land, and must deliver greater economic returns, than cattle pastures. That’s what most of the current land grabs in Africa are about. That’s why the World Bank calls the continent’s millions of square kilometres of unfenced savanna “the world’s last large reserve of underused land”.

‘But are the great grasslands really “underused”? . . .

There have been remarkably few analyses of what economists term the “opportunity costs” of big irrigation schemes. Of how they stack up against the pastoral alternative? So the findings of a new investigation from Ethiopia could, and certainly should, reverberate across Africa.

‘Ethiopia’s government has high ambitions for economic development, but sometimes appears to have less regard for herders. . . .

‘Is this long-standing land grab worth it? Does it bring development? A new economic analysis of the valley from Roy Behnke and Carol Kerven of Imperial College London, for the International Institute for Environment and Development, called Counting the Costs, says not. . . .

‘[T]he authors find that, in the Awash valley, revenues per hectare are higher on areas still devoted to livestock than they are for either sugar or cotton plantations. Sugar cane farming, the more profitable of the two, only matches the returns from livestock one year in four.

‘Behnke and Kerven conclude that, here at least, “pastoralism is consistently more profitable than either cotton or sugar… while avoiding many of the environmental costs associated with large-scale irrigation projects.”

‘Not only do the giant irrigation schemes, behind their high fences, fail to deliver cash, they also damage soils, undermining the future productivity of the land. . . .

The lessons here matter for the whole of the continent. As Behnke and Kerven put it: “The Awash valley illustrates what lies in store for pastoral areas, if African governments pursue a policy of modernised agriculture by displacing mobile livestock production.”